1. Field of the Invention
The present invention relates to a locator for a material sheet, and particularly to a locator for confining a distance between two end parts of a material sheet effectively.
2. Description of Related Art
Normally, aligning or correcting the position of a material sheet such as a glass substrate, a sheet of chip, or the like in a load-lock chamber and a heat chamber during the operation of plasma enhanced chemical vapor deposition is performed by way of two opposite stoppers disposed at two lateral sides of the material sheet. There is no doubt that the two lateral sides of the material sheet can be confined properly at both lateral sides thereof simply by way of these two opposite stoppers and can reach an expected effect. However, the positions at both ends of the material sheet are not possible to be located positively and especially it is impossible to prevent from the slide deviation effectively.
The preceding way for locating the material sheet makes the position of the glass substrate or the chip sheet prior to enter the process chamber different from the calibrated position of the robot. Thus, the film is unable to deposit at a right position during the operation of film depositing, that is, a phenomenon of the so-called film shift may occur.
The film shift may result in incomplete plating at the edge of the material sheet, and even more, the film is plated to exceed the boundary of the sheet. Also, it can occur not only a phenomenon of non-uniform film thickness on the surface of the sheet caused by a change of air current but also a phenomenon of arcing to influence the life span of component parts thereof.
Furthermore, the material sheet may elongate forward and backward due to error resulting from fabricating, delivering, thermal expansion, or other reasons. Especially, it is noted that heating is one of required steps for the operation of plasma enhanced chemical vapor deposition. Hence, the locator with regard to lateral positioning is not possible to prevent the material sheet from the deformation of both end parts thereof.
An object of present invention is to provide a locator for a material sheet, in which opposite stoppers being disposed at front and rear ends of the material sheet corresponding the length of the slot sheet for confining a distance between two end parts of a sheet effectively.